/* inflate_util.c -- data and routines common to blocks and codes
 * Copyright (C) 1995-2002 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

#include "zutil.h"
#include "infblock.h"
#include "inftrees.h"
#include "infcodes.h"
#include "infutil.h"


/* And'ing with mask[n] masks the lower n bits */
local const uInt inflate_mask[17] = {
    0x0000,
    0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
    0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};


/* copy as much as possible from the sliding window to the output area */
local int inflate_flush( /* s, z, r) */
    inflate_blocks_statef* s,
    z_streamp z,
    int r)
{
    uInt n;
    Bytef* p;
    Bytef* q;

    /* local copies of source and destination pointers */
    p = z->next_out;
    q = s->read;

    /* compute number of bytes to copy as far as end of window */
    n = (uInt)((q <= s->write ? s->write : s->end) - q);
    if (n > z->avail_out) n = z->avail_out;
    if (n && r == Z_BUF_ERROR) r = Z_OK;

    /* update counters */
    z->avail_out -= n;
    z->total_out += n;

    /* update check information */
    if (s->checkfn != Z_NULL)
        z->adler = s->check = (*s->checkfn)(s->check, q, n);

    /* copy as far as end of window */
    zmemcpy(p, q, n);
    p += n;
    q += n;

    /* see if more to copy at beginning of window */
    if (q == s->end)
    {
        /* wrap pointers */
        q = s->window;
        if (s->write == s->end)
            s->write = s->window;

        /* compute bytes to copy */
        n = (uInt)(s->write - q);
        if (n > z->avail_out) n = z->avail_out;
        if (n && r == Z_BUF_ERROR) r = Z_OK;

        /* update counters */
        z->avail_out -= n;
        z->total_out += n;

        /* update check information */
        if (s->checkfn != Z_NULL)
            z->adler = s->check = (*s->checkfn)(s->check, q, n);

        /* copy */
        zmemcpy(p, q, n);
        p += n;
        q += n;
    }

    /* update pointers */
    z->next_out = p;
    s->read = q;

    /* done */
    return r;
}